FAA Aviation Mechanic Powerplant (AMP) practice questions
335 free questions with answers and explanations.
- 1.A technician inspects the combustor liner of a turbine engine and notes rows of small holes and slots along the liner wall. What is the primary purpose of these holes?Turbine Engines
- 2.A mechanic is comparing the oil pressure and scavenge pumps in a turbine engine lubrication system. The scavenge pump has a significantly greater pumping capacity than the pressure pump. What is the primary reason for this design?Fuel, Induction and Lubrication
- 3.A mechanic is servicing a ground-adjustable pitch propeller on a light aircraft. When can the blade angle of this type of propeller be changed?Propellers
- 4.A turbofan engine's fan case incorporates a heavy Kevlar or steel containment ring surrounding the fan blade path. What is the primary purpose of this structural feature?Turbine Engines
- 5.A hydromechanical fuel control unit (FCU) on a turbine engine schedules fuel flow to the engine. Which combination of inputs does the FCU primarily use to compute the correct fuel flow?Turbine Engines
- 6.A cylinder on a reciprocating engine shows excessive oil consumption and bluish-gray smoke from the exhaust at idle power, while a differential compression check shows normal readings with no unusual hissing at the intake or exhaust ports. A technician suspects the intake valve guide has excessive stem-to-guide clearance. What is the most likely mechanism causing the oil consumption in this case?Reciprocating Engines
- 7.In a continuous-flow fuel injection system, what is the primary function of the individual fuel discharge nozzles installed at each cylinder's intake port?Reciprocating Engines
- 8.A mechanic is checking the float level on a float-type carburetor and finds it set higher than the manufacturer's specification. What is the most likely effect on engine operation?Engine Inspection
- 9.A mechanic is inspecting a reciprocating engine equipped with an oil dilution system used for cold-weather starting. How does this system function?Fuel, Induction and Lubrication
- 10.During a ground start, a turbine engine's EGT rapidly rises above the specified start limit while N1 remains very low and slow to accelerate. Which start condition is being experienced?Turbine Engines
- 11.A pilot reports that a reciprocating engine runs rough after extended ground operations at low power but smooths out after a brief application of high power. A technician suspects spark plug fouling. What is the most likely cause and appropriate corrective action?Ignition and Starting Systems
- 12.A technician is troubleshooting an oil temperature gauge that reads consistently high during ground runs, while oil pressure remains normal. Inspection reveals the thermostatic bypass valve (Vernatherm) in the oil cooler is stuck in the bypass position. What effect does this have on the lubrication system?Reciprocating Engines
- 13.A pilot operating a fuel-injected engine at high cruise altitude on a hot day is advised to switch on the electric fuel boost pump. What problem is this action primarily intended to prevent?Fuel, Induction and Lubrication
- 14.A technician is calculating the compression ratio of a cylinder that has a swept (displacement) volume of 85 cubic inches and a combustion chamber clearance volume of 10 cubic inches. What is the compression ratio?Reciprocating Engines
- 15.A turbofan engine manufacturer specifies that the engine is 'flat rated' to an outside air temperature of 30°C. What does this rating mean for engine performance?Turbine Engines
- 16.A turbine engine ignition system uses a capacitor discharge (CD) exciter unit to fire the igniter plugs. Which statement best describes how this system produces the high-energy spark required for turbine ignition?Ignition and Starting Systems
- 17.A technician is diagnosing a lifter noise complaint on an engine equipped with hydraulic valve lifters. During engine operation, the hydraulic lifter is designed to automatically compensate for valve train clearance. What component within the hydraulic lifter allows this automatic clearance adjustment?Reciprocating Engines
- 18.A technician is timing a magneto to the engine (external timing) rather than performing internal E-gap timing. Which of the following describes this procedure?Reciprocating Engines
- 19.A mechanic is briefing an owner-pilot on the fuel system of a light twin equipped with individual tanks in each wing. Which statement best describes the primary purpose of the fuel selector valve?Fuel, Induction and Lubrication
- 20.A technician installs new piston rings in a reciprocating engine cylinder and checks ring end gap by squaring the ring in the bore with an inverted piston, then measuring the gap with a feeler gauge. The measured gap is 0.006 inch, but the overhaul manual specifies a minimum gap of 0.010 inch. What should the technician do?Engine Inspection
- 21.A mechanic discovers that the pressurization valve on a turbine engine's oil tank is stuck in the closed position, preventing bleed air from pressurizing the tank. What is the most likely operational effect of this defect?Fuel, Induction and Lubrication
- 22.A technician is comparing a low-tension magneto ignition system to a conventional high-tension system on a reciprocating engine. What is the main operational advantage of the low-tension system?Ignition and Starting Systems
- 23.During the start sequence of a turbine engine, the exhaust gas temperature rapidly exceeds the specified start limit while RPM is still low. Which condition most likely caused this hot start?Ignition and Starting Systems
- 24.A radial engine's electric starter is connected to the crankshaft through a starter adapter. What two functions does the starter adapter typically provide?Reciprocating Engines
- 25.A turboprop engine's propeller shaft torquemeter indicates 3,000 ft-lb of torque while the propeller shaft is turning at 1,500 RPM. Using the formula HP = (Torque × RPM) / 5,252, what shaft horsepower is being produced?Turbine Engines
- 26.A technician replacing main bearings on a reciprocating engine crankshaft installs plain (sleeve-type) bearings rather than ball or roller bearings. What is the primary advantage of plain bearings in this high-load, high-speed application?Reciprocating Engines
- 27.A technician removes a turbine engine's magnetic chip detector plug during scheduled maintenance. What is the primary purpose of this component?Turbine Engines
- 28.A technician measures the distance from the centerline of a crankshaft main journal to the centerline of the connecting rod journal (the throw) and finds it to be 2.5 inches. What is the piston stroke of this engine?Reciprocating Engines
- 29.A technician is reading a turbine engine maintenance manual that references 'engine stations' for locating components. In what order are engine stations numbered along the engine?Turbine Engines
- 30.During a ground run of a turbocharged reciprocating engine, a mechanic rapidly advances the throttle and hears a loud banging noise from the turbocharger while manifold pressure fluctuates wildly before stabilizing. This condition is most likely caused by:Fuel, Induction and Lubrication
- 31.A mechanic is adjusting the float level on a float-type carburetor during overhaul. If the float level is set too high, what is the most likely result during engine operation?Fuel, Induction and Lubrication
- 32.A mechanic inspecting a turbocharger finds excessive radial and axial play when moving the compressor wheel shaft by hand, along with light rub marks on the compressor housing. This condition most likely indicates:Engine Inspection
- 33.A twin-engine aircraft experiences an engine failure in flight. Why does the pilot feather the propeller on the failed engine?Propellers
- 34.On a horizontally opposed four-cylinder engine viewed from the rear (accessory case), cylinder numbering follows standard convention. Where is cylinder number 1 located?Reciprocating Engines
- 35.During climb, a turbojet engine experiences a compressor stall accompanied by loud banging noises, vibration, and a rise in exhaust gas temperature. What is the correct immediate corrective action by the pilot?Turbine Engines
- 36.A technician is reviewing the valve timing diagram for a reciprocating engine and notes that the exhaust valve opens well before bottom dead center (BDC) on the power stroke. What is the primary purpose of this early exhaust valve opening?Reciprocating Engines
- 37.During a ground run, a mechanic performs an idle mixture check on a float-type carburetor by slowly moving the mixture control toward idle cutoff while watching the tachometer. The engine RPM begins to decrease immediately with no momentary rise before it drops. What does this indicate?Fuel, Induction and Lubrication
- 38.A student pilot asks a mechanic why the manifold pressure gauge on a normally aspirated reciprocating engine reads well below the local atmospheric pressure when the engine is idling on the ground. What is the correct explanation?Fuel, Induction and Lubrication
- 39.A mechanic is explaining propeller theory to a student. The student asks how 'effective pitch' differs from 'geometric pitch.' Which statement correctly describes effective pitch?Propellers
- 40.A mechanic is comparing carburetor and fuel injection systems on reciprocating engines. Which of the following is a primary advantage of a fuel injection system over a float-type carburetor?Fuel, Induction and Lubrication
- 41.An oil analysis laboratory reports increasing concentrations of iron and chromium in successive spectrometric oil analysis (SOAP) samples from a reciprocating engine, while other metals remain stable. What should the mechanic suspect based on this trend?Fuel, Induction and Lubrication
- 42.A four-cylinder aircraft engine has a bore of 5.0 inches and a stroke of 4.0 inches. What is the approximate total piston displacement of this engine?Reciprocating Engines
- 43.A mechanic is troubleshooting an aircraft fuel tank venting system after a pilot reports fuel starvation symptoms despite an indicated full tank. Which condition would most likely cause this problem?Fuel, Induction and Lubrication
- 44.A technician is inspecting a propeller assembly and notes a streamlined fairing covering the hub at the front of the propeller. What is the primary purpose of this component?Propellers
- 45.A mechanic is studying the fuel nozzles installed on a turbine engine combustor and notes that they are duplex (dual-orifice) rather than simplex nozzles. What is the primary reason for using duplex nozzles?Fuel, Induction and Lubrication
- 46.Inside a magneto coil assembly, the secondary winding consists of many turns of very fine wire wound over the primary winding on a common iron core. What is the primary function of this secondary winding?Ignition and Starting Systems
- 47.During a preflight inspection, a technician drains fuel from the aircraft's fuel strainer sump into a clear sample cup. Why is this check performed?Fuel, Induction and Lubrication
- 48.Some magnetos used on radial engines incorporate a retard breaker (impulse coupling alternative) mechanism. What is the purpose of the retard breaker during engine starting?Ignition and Starting Systems
- 49.During overhaul, a technician installs a new plain bearing insert into a connecting rod housing bore. Before the rod cap is torqued, the bearing half protrudes slightly above the parting surface because its circumference is slightly greater than the housing bore. This designed characteristic is known as bearing crush, and its main purpose is to:Reciprocating Engines
- 50.A direct-cranking electric starter on a reciprocating engine uses a Bendix drive to engage the engine ring gear. What principle allows the drive pinion to move forward and mesh with the ring gear when the starter motor is energized?Ignition and Starting Systems